In some of the vehicle floor structures, convex-shaped or concave-shaped beads are provided over substantially the entirety of a floor panel, the beads centered around portions where side sills go across cross members (for example, see Patent Document 1).
These beads can remarkably increase the rigidity of the floor panel while reducing the weight of a vehicle body. That is, in a floor panel provided with beads in this manner, a load applied to the floor panel is transmitted in directions in which the beads extend. Therefore, this property is used to transmit a collision load at the time of a frontal vehicular collision or a rear vehicular collision to side sills via the floor panel. This allows the load to be distributed. As a result, the load borne by the individual members can be decreased.    Patent Document 1: Japanese Unexamined Patent Publication, First Publication No. 2006-298076
However, in the above-mentioned prior art, there are cases where a floor panel is bent as a result of the beads failing to resist a load when a collision load is transmitted to the floor panel at the time of a frontal vehicular collision or a rear vehicular collision. When the floor panel is deformed like this, the problem is that transmission of the load to side sills is obstructed, preventing the load from being distributed.
Furthermore, in the above-mentioned prior art, the beads provided on the floor panel make it possible to enhance the rigidity of the floor panel itself. However, at the side collision of a vehicle, the problem is that the impact load which acts from a side portion does not sufficiently act on the floor panel, that is, the impact load cannot be effectively received by the entirety of the floor panel. Moreover, when it is configured such that this impact load is received only by the floor panel, the rigidity of the floor panel must be further enhanced. This increases vehicle weight, leading to problems with improvements in fuel efficiency.
Therefore, it is an object of the present invention to provide a vehicle floor structure which, at the time of a frontal vehicular collision or a rear vehicular collision, is unlikely to deform and is capable of effectively distributing a collision load.
Furthermore, it is another object of the present invention to provide a vehicle floor structure which effectively transmits an impact load acting at the time of a side vehicular collision to a floor panel and is capable of decreasing a load borne by the floor panel.